Peter SCAMBLER, Institute of Child Health, University College London (UK)

DiGeorge Syndrome, or the 22q11.2 deletion syndrome, is the most frequent human congenital heart syndrome. Investigators in this Leducq network hope to understand the origins of the problem. DiGeorge Syndrome, and other congenital heart syndromes, often involve craniofacial abnormalities. New findings have linked some of the most common human congenital heart defects to a progenitor cell population named the cardiopharyngeal mesoderm (CPM), which as the name implies, forms not only the heart, but part of the face and neck. This Leducq network’s multidisciplinary team will investigate the role of the Tbx1 gene, which is essential for development of the CPM cell population and the formation of the heart, relying upon models in the mouse and the sea squirt Ciona; mice recapitulate faithfully the human patient phenotype and Ciona has recently emerged as an excellent model for CPM biology. Investigators hope to gain novel insights concerning 22q11.2DS pathogenesis, and the mechanisms controlling cardiopharyngeal development. The results should add considerably to our knowledge of genetic heart defects, and could have implications for the diagnosis and prognosis of human patients.